Abstract: Disclosed are methods for preparing a high-viscosity non-hazardous bitumen composition for transportation in a railcar, wherein the method may include: (a) providing to a fractionator system a low-viscosity bitumen composition previously residing in a pipeline having a first viscosity and comprising a miscible blend of hydrocarbons, which blend was prepared by mixing a first diluent composition with a first bitumen composition; (b) heating the low-viscosity bitumen composition in the fractionator system at an operating temperature of from 170 C to 232 C to provide a first light fraction and a first heavy fraction; (c) removing at least a portion of the first heavy fraction from the fractionator system, wherein the first heavy fraction has a second viscosity that is higher than the first viscosity; (d) forming a high-viscosity non-hazardous bitumen composition from at least a portion of the first heavy fraction; and (e) directing the high-viscosity non-hazardous bitumen composition to a railcar.